Signal-lens



(No Model.)

G. A. MAGBBTH. Y

SIGNAL LENS; .-No. 351,609. y Patented oct. 26, 1886.

l 7n i UNITED STATES PATENT QEEICE.

GEORGE A. MACBE'IH, OF PITTSBURG, PENNSYLVANIA.

SIGNAL-LENS.

SPECIFICATION forming part of Letters Patent No. 351,609, dated Octcber26, 1886.

.Application filed April 19, 1886. SerialNo. 199,439. (No model.) I

To all whom it may concern.-

Be it'known that I, GEORGE A. MAcBE'rH,

of Pittsburg, in the county of Allegheny and State of Pennsylvania, haveinvented anew and useful Improvement in Signal-Lenses; and

' lenses are formed corrugated to reduce the thickness of the glasstherein, several corrugations having cumzed faces formed ou the lens andthe faces ofthe corrugations transmitting and dellecting the light, inthe same manner as if a bullseye lens were employed, the thickness andweight of the lens being reduced in this manner; and at the same time,where the lens is formed of colored glass, as the thick- -ness of thelens is substantially the same throughout, the light will vpenetrate thelens with The saine ease throughout its entire face, it being found thatin bulls-eye lenses formed of glass of certain colors the centralportion of the lens is so vthick as to prevent the easy penetration ofthe light and the principal light from the lens is obtained through theouter portions thereof.

The special objects off/my invention are to protect these corrugatedlenses from fracture or injury by contact with or blows from otherV hardsubstances, and to prevent the settling of dust or dirt in thecorrugations of the lenses, as well as to facilitate the cleaning ofthelenses. To 'these ends I employ with the lens a faceprotector having corrugations on its inner. face corresponding in position tothose of thelens,y and having a smooth outer face, this faceprotector aiordingprotection to the lens from injury and presenting a smooth faceon'whichthe dust will notsettle,and which cau be easily cleaned if blurred inany manner. I have-also improved these lenses in other particulars, ahereinafter set forth and claimed.

. To enable. others skilled in the art to make and use my invention, Iwill describe the same more fully, referring to the accompanyingdrawings, in which- Figure l is a cross-section of a railway or Likeletters of reference indicate like parts in each.

' Where my invention is employedin connection with a corrugatedsemaphore-lens, as

shown in Figs. 1, 2, 3, and 4, I generally employ for the lens properflint or lead glass, and for the face-protector crown or lime glass, therefracting power ofthe intglass being greater than that of thecrownglass, so that the light transmitted through the lens is firstdefiected by the flint-glass lens in substantially the line desired, andin passing through the crownglass face-protector it is deflected butlittle from the course in which it is thrown by the flint-glass lens. Iprefer to employ flint-glass for the lens proper, for the reason, amongothers, that it is not so liable to crack or break under changes oftemperature, and it is eX- posed directly to the heat of the lamp. Thecombined lens may, however, be formed with the lens proper ofcrown-glass and thefaceprotector of dint-glass, the curvature of thefaces of the corrugafions being, of course, changed according to thedirection in which the light is to be thrown, or, in some cases, bothlens and face-protector may be formed of the same kind of glass, thecorrugations being formed of such curvature as to deflect the light inthe desired direction, or the inner and outer faces of the protectorbeing substantially parallel or of the same curvature, so as to havelittle or no effect upon the course of the light.

The lens proper, a, as well as the face-protector b, are pressed toshape, the faces of the corrugations c of the lens being convex, and thecurvature thereof depending upon the desired deflection of the lightthrough the lens, the central portion or bull7 s-eyc, d, and thefaccsofthe corrugations of the lens being Sections of circles drawn from theSallie cellter, this being well known to lens manufacturers. At theouter edge of the lells I prefer to fornl a plain or flat portion orface, forming a bearing-face extending arolllld the outer corl'ugation,as at c.

The face protector b is provided with a slnooth or plnin outer face, f,and its illller face is generally provided with corrugationscorresponding in positioll to tllose on the corrugated face of thetells, so that when the two parts of the colllbined lens are placedtogether they will tit together and act to sllpport each other, thecorrugated face-protector b having the concave central portion, g, andthe corrugations h corresponding in position to the corrngations of thetells proper, and the edge or face i forming a bearing-face extendingaround the outer corrugations and fitting against the bearing face orportion e of the lens proper. The reti-acting or detlecting power of theilintglass lens is greater than that of the crownglass face protector,alld as the light passes thlougll the lens it is deflected in thedirection desired, or possibly a little lnore than desired,- and as itpasses through the face-protector it is deflected slightly in theopposite direction, the angle of deflection through the face-protectorheilig hilt slight, or passes directly through the face-protector, wherethe inner alld outer faces thereof are substantially parallel.

The curvature of the corrugated faces of the lens and lts face-protectorcan be changed, so as to throw the light passing tllrough the coinvbilled lens ill whatever direction desired. For example, ill the lensshown ill the enlarged view,Fig. 4,the face-protector will actto spreadthe light slightly after it passes through the lells propel', thecurvature of the faces of the corrugations lt of the lace-protectorheilig but slightly greater than that ol" the smooth convex outer face,f, thereof; but where the outer facej' and the faces of the corrugationsh are drawn from ille sallle circle the light will pass directly throughthe 1`aceprotector. being directed ill the course di-sired entirelybythe lens propel'. lll such ease the inner and outer lace of ttlcprotector to be made smooth, as Shown ill Fig.

As the edges of the corrugntions 7L of the face-protector lit againstille edges of the corrugations c of the lens, it is evident that tlleyact to support each other, and ill case of blows llpoll the outersurface ot' the face protector there is but little fear of fracture ot'the saine, while there is no fear whatever of chipping or det'tleing theslllootll outer surface of the taceprotector, alld tllcre is noliability ot' dust or dirt settling upon the outer surface of theface-pl-otector and thus preventing the passage of the light tllroughthe sallle. As the bearing portiolls or laces et' ofthe two pal-ts ofthecolllbilled lells lit against each other, no opportullity is ali-'ordedfor the entrance or settlementof dtlst or dirtbetween the tivoparts ofthe lens,and the twoparts are further protected from such action bycenlent or like lnaterial placed between these fiat faces and forming atight or sealed joint.

The two parts of the lens4 may be secured together in any suitablemanner, citller by pasting cloth or other suitable material around theedges of the lens, or, as sllown ill the drawillgs, by securing the twoparts of the lens within an annular sheet metal ring, as at It, thisring having a lip or lips, l, fitting onto the outer surface of the lensor face-protector, while the other edge of the ring is turned up ontothe opposite face of the combined lens.

The outer laces of either the lens or the face-protector may be slightlycurved.' as desired, either for the purpose of correcting the deliectionofthe light as it passes through the colnloined lens, or lor any otherreason, a con- Vex-faced protector being shown to the right ill Fig. l,and ill Fig. 4, as before referred to.

When llly invention is elllployed with polelanterns,or other lanternshavillg corrugations extending alou nd the saine, as shown ill Figs. 5and 6, the tace-protector b, and, if desired, the lens or lantern globe.nlay be formed in sections alld secured within the lantern ill anysuitable manner, the lantern sllowll having perpendicular standardsnaextending fro n'l the base lt to the top p, and the lclls andface-protector being secured between these standards.

The construction of the combined lens ls substantially the same in thisforln of lanterll as in the signal-lanterns above described, except thatthe corrugations extend horizontally across the outer face of the lellsor lantern globe and the inller face of its face-protector, instead ofill a circle, as ill the ordillary semaphore-lens. The flat portioll orfaces e vi of the two parts of the eolnbilled lens [it against eachother so as to support each otller, as above described, and tlleir edgesmay he secured in any sllitable manner for fastening Within the lantern.Then my inlprovelllellts are employed with colored signal-lanterns,[form the inner portion or lens proper of the glass ofthe required color.alld the faeeprotcctor of colorless glass, so that in case of acridentto the f-lce-proteetor the colored signallight still remains, and thereis no liability ot" accident caused by a false sigllal.

Vtlen illy illlproved signal-lenses are ill use, the ligllt frolnthelantern passes first through the corrugated lens and is deflectedthereby, alld then through the face-protector, being either deflected toa great extent by the flintglass lens, and this deflection slightlycorrected or turned in the opposite direction by the crown-glassface-protector, or heilig deliected slightly by the crown-glass lens andto a nluch v greater extent by the Hint-glass tace-protector,

according to the curvature of the lens and its outer protector, or theentire deliection being unparted by the lells, as above described.

In handling the lanterns, as the outer faces of IIO the lenses are plainor smooth, there is little or no liability of the chipping or breakingof the same, as there is no rough place to catch or dust, it is evidentthat the lenswill remain clean much longer than the ordinary corrugatedlens, and that the difficulty ofthe light being impaired from this canseis entirely overcome, while at the same time the cleaning of the lens isgreatly facilitated, there being no rough faces to wipe ont, and as theedges of the lens and face-protector aresealed it is evident that nodirt can enter between the faces.

Where the iiint glass lens and crown-glass face-protector are employed,the difficulty ot' the cracking of the lenses on account of the unequalheating thereof is to a great extent overcome, as the flint glass isnot'so liable to crack by overheating, and it is more directly eX- posedto the heatof the lamp.

I ain aware that plane colored glass has been employed with colorlesslenses, either back of or in front of the lens to impart the color ofthe plane glass to the light passing through the lens, the planeglass,when placed in front of the lens,being supported in aseparateslide or holder therefrom. Though this plane glass might to some extentprotect the corrugations of the lens froin dust, yet no such protectionfrom dust was obtained as where the lens and face-protector fit againsteach other, and the plane glass gave practically nop rotection fromblows, as it was not sufficiently supported to sustain therough handlingthesesig nal-lanterns receive, and if the plane glass was fractured, asit was colored and the lens colorless,it caused the lantern to give afalse signal, and in some cases was the sourceof serious accidents.

What I claim as my invention,and desire to secure by Letters Patent, is

1. The combination, with a corrugated lens, of a face-protector providedwith an inner face having corrugations corresponding in position tothose of the lens, and asniooth outer face, substantially as and for thepurposes set forth. Y 1

2. The combination, with a corrugated lens, of a face-protector formedvof glass having a different refracting power, and having corrugationscorresponding-in position to those of the lens, and asmooth outer face,substantially as and for the purposes set forth.

3. The combination, with the corrugated lens a, having the bearing faceor faces e beyond the corrugated portion thereof, of the faceprotectorb, having the corresponding bearing face or faces fitting against saidbearing face or faces e, substantially as and for the purposes setforth. 1

4. The combination, with a corrugated lens having a bearing face orfaces beyond the corrugated portion thereof, of a face-protectorprovided with-an inner face having corrugations corresponding inposition to those of the lens, and having acorresponding bearing face orfaces fitting against the bearing face or faces of the lens.substantially as and for the purposes set forth. Y i

5. The combination, with the corrugated lens a, having the bearing faceor faces e beyond the corrugated portion thereof', of the face-protectorb, having the corresponding bearing face or faces t' fitting against thefaceV or faces c, and suitable seali ng material betweensaidbeariug-faces,substantially as and for the purposes set forth.

6. The combination, with a corrugated lens, of a faceprotector fittingagainst the lens having a smooth outer -face and a supporting ring orband fitting around the edges of the lens and face-protector,substantially as and for the purposes set forth.

7 The combination, with a corrugated lens, of a faceprotector providedwith an inner face having corrngations corresponding in position tothose of the lens, andacurved smooth outer face, substantially as andfor the purposes set forth.

8. The combination, with a corrugated lens formed of colored glass, of aface-protector formed of colorless glass and fitting against the lens,substantially as and for the purposes set forth.

In testimony whereof I, the said GEORGE A. MAOBETH, have hereunto set myhand.

l GEORGE A. MACBETH.

Witnesses:

-JAMns I. KAY,

J. N. COOKE.

IOO

